Motor vehicles are increasingly designed as hybrid vehicles, whose drive unit is provided by a hybrid drive. The drive unit comprises an internal-combustion engine and, in addition, an electric motor. A transmission is placed between the hybrid drive of hybrid vehicle and its driven gear. The operation of the transmission is controlled and/or regulated by a transmission control device. The operation of the electric motor is controlled and/or regulated by a hybrid control device. The operation of the internal-combustion engine is controlled and/or regulated by an engine control device.
When a motor vehicle is operating under a hybrid-mode ride, the drive torque is provided both by the internal-combustion engine and the electric motor of the hybrid drive at the output of the hybrid vehicle. At a purely electric ride, the internal-combustion engine of the hybrid drive is disconnected from the output and preferably stopped. If a change from the hybrid-mode ride into a purely electric ride occurs in a deceleration fuel cut-off of the internal-combustion engine of the hybrid drive, the internal-combustion engine in deceleration fuel cut-off is disconnected from the drive and stopped, wherein in hybrid vehicles known in practice this is done so that the internal-combustion engine operated in the deceleration fuel cut-off operation increases its torque over a predetermined course to approximately zero, and then a clutch interposed between the internal-combustion engine and the electric motor is opened in order to decouple the internal-combustion from the output. A disadvantage here is that in order to increase the torque of the internal-combustion engine, the engine is fired and then needs the same fuel accordingly.